War and religion

The relationship between war and religion has dated back to the dawn of human civilization. Many religions believe that wars can be justified under some circumstances such as self-defense or holy war, while other religions oppose violence as a whole and support pacifism.

Background
War is a common occurrence with high costs: these costs include death (including civilian/child casualties), poverty, starvation, national bankruptcy, and destruction (of agriculture, as well as of towns and cities). Religions have differing views on war, especially contrasting whether they can be just, or whether violence should never be justified.

Hinduism
In Hinduism, there are different warrior gods, and, if there is a just cause, war can be considered. However, the concept of ahimsa (noninjury) involves the resolution of a problem without war or casualties, and this concept was advocated by Mahatma Gandhi.

Buddhism
In Buddhism, the concept of ahimsa is also present, and Buddhists also believe in nonviolence, being generally opposed to war (except for extreme situations). The religion as a whole is generally anti-war, and the only justification is protecting the interests of those who could not help themselves. War is almost never fought over material possessions, as Buddhists are opposed to unnecessary attachment.

Judaism
Judaism believes that some wars are justified by God, with Moses' successor Joshua exterminating the Canaanites, Jebusites, and Hittites under God's orders. Under King David, the Israelites fought against the Philistines. However, in Reform Judaism, peace is heavily emphasized through negotiations and protests.

Christianity
Christianity has conflicting views on war: some, including the medieval Catholic Church, supported crusades (holy war against non-Christians), while others support Jesus' pacifism and oppose war. Saint Augustine of Hippo coined the "just-war theory", believing that war was just if it was a lst resort, if it was waged by a legitimate authority, if it was for a just cause, if there was a rational possibility of success, if it had the right intention (such as re-establishing peace), it it was proportional, and if civilian casualties are avoided. However, Jesus himself told his followers to turn the other cheek if struck by someone, told his followers to do no evil for evil, and opposed violence.

Islam
Islam also has a concept of just wars, believing that, if there is no way to avert it, and if war will protect Muslims from their enemies, war can be justified. The concept of "defensive jihad" authorizes war in defense of the ummah (the Muslim world) when it comes under foreign attack.